IRAP and REMAP-Based Genetic Diversity among Iranian, Turkish, and International Durum Wheat (Triticum turgidum L.) Cultivars

Retrotransposons (RTNs) are a major source of genomic changes in plant genomes and, therefore, are extensively used as ideal molecular markers for genetic variability, DNA fingerprinting, and genetic mapping studies in plant species. In the present study, two RTN-based marker systems, inter-retrotransposon amplified polymorphisms (IRAPs), and the retrotransposon-microsatellite amplified polymorphisms (REMAPs) were used to assess genetic variability and structure in a collection of 94 durum wheat genotypes. In general, 63 and 141 loci were amplified using 6 IRAP and 15 REMAP primers, respectively. Percentage of polymorphic loci (PPL) in the studied collection for IRAP and REMAP markers were 47.15% and 47.81%, respectively. The average of expected heterozygosity (He), number of effective alleles (Ne), and Shannon's information index (I), separately estimated based on IRAP and REMAP data, were not considerably different. A model-based Bayesian method and cluster analysis using Neighbor joining (NJ) algorithm depicted five clusters. A moderate level of inter-group genetic variability was detected among the clusters (11%) obtained from STRUCTUR software (PhiPT =0.111; P=0.001) with the vast majority of variation (89%) still uncaptured within groups. Most of the accessions and landraces from Iran aggregated together in clusters I and III with the cultivars from Turkey. Also, Iranian and foreign durum wheat landraces were assigned to different clusters or subpopulations in both clustering methods. In conclusion, the results showed that the genetic diversity of Iranian durum wheat is low and it is necessary to extend the genetic base of durum wheat germplasm in Iran.